Fluid pressure brake



April 2611938- H. R. FUEHRER FLUID PRESSURE BRAKE Filed June 50, 1956mmm I 1 "'11 illllllmll Willi.

1NVENTOR HERBERT F?. FUEHRER QW. d/

ATTORN EY Patented pr. 26, 1938 UNITED STATES PATENT eerie TheWestinghouse Air Brake Company, Wilmerding, Pa., a corporation ofPennsylvania Application June so, 1936, serialfNo. 83,1075

21 Claims.

This invention relates to a uid pressure brake and more particularly toan improvement in the brake controlling valve device shown in thecopending application, Serial No. 67,274, of Ellery R. Fitch, led March5, 1936.

The brake controlling valve device shown in the above identifiedapplication comprises a movable abutment subject to the opposingpressures of the fluid in the brake pipe and of the iiuid in a pres*sure chamber and valve means operable by said abutment for controllingemergency applications of the brakes, and for controlling a passagethrough which uid under pressure may be supplied irom the brake cylinderto the brake pipe. This movable abutment also controls a communicationthrough which fluid under pressure may flow from the pressure chamber tothe brake pipe at a rate which will permit the pressure of the fluid inthe pressure chamber to reduce substantially as rapidly as the pressureof the fluid in the brake pipe is reduced on a reduction in brake pipepressure at a service rate tol thereby prevent the development ofsufficient differential between the pressures in the pressure chamberand in the brake pipe to cause the movable abutment to be moved to aposition in which the einer* gency valve device is operative to effectthe venting of iiuid under pressure from the brake pipe and therebycause an emergency application of the brakes.

This passage is controlled by a check valve which operates to cut offthe flow of fluid therethrough from the brake pipe to the pressurechamber, and a by-pass passage extending 33 around the check valve isprovided through which fluid may be supplied to the pressure chamberfrom the brake pipe at a restricted rate. As fluid .is supplied to thepressure chamber only at a restricted rate the pressure in the pressurechamber will not increase as rapidly as the pressure in the brake pipeis increased, and suflicient differential in pressure will be developedbetween the brake pipe and the pressure chamber to move the abutment toits inner release position in which communication is established betweenthe brake cylinder and the brake pipe.

In the emergency valve device shown in the above identified applicationa ball type check valve is employed and it is moved to its seatedposition by fluid flowing from the brake pipe to the pressure chamber.There is a possibility, if the rate of increase in the pressure of thefluid in the brake pipe is relatively slow, as may be the case at therear end of a long train, so that the rate 5j; of ow of fluid from thebrake pipe to the pressure chamber is relatively slow, that the fluidflowing through this passage will not exert sufficient force on thisball check valve to move it to the seated position to restrict the flowof fluid from the brake pipe to the pressure chamber. As a result thepressure of the fluid in the pressure chamber will increasesubstantially as rapidly as the pressure of the fluid in the brake pipeand no pressure dilferential will be created to move the abutment to theinner release position.

It is an object of this invention to provide a brake controlling valvedevice operative to effect emergency applications of the brakes, andhaving a movable abutment subject to the opposing pressures of the fluidin the brake pipe and of the fluid in a pressure chamber, the abutmentconn trolling a communication through which fluid under pressure may owbetween the brake pipe and the pressure chamber, improved means beingprovided to restrict the rate of flow of fluid from f the brake pipe tothe pressure chamber through this passage.

A further object of the invention is to provide an emergency valvedevice of the type described and having improved valve means controllinga communication through which iiuid flows between the brake pipe and thepressure chamber, this valve means being operative on movement of theabutment from the emergency application position towards the releaseposition to restrict J the rate of flow of iiuid from the brake pipe tothe pressure chamber.

Another object of the invention is to provide an emergency valve deviceof the type described and in which the valve means controlling the iiowof fluid from the brake pipe to the pressure chamber is operative torestrict the rate of flow of fluid to the pressure chamber irrespectiveol the rate of increase in. brake pipe pressure.

A further object of the invention is to provide an emergency valvedevice of the type described and having valve means to cut of the iiowof fluid from the brake pipe to the pressure chamber on movement of theabutment from the emergency application position to the release positionuntil a predetermined pressure has been established in the brake pipe, avalve device being provided to also control a communication between thebrake pipe and the pressure cham ber and being operative to close saidccminunication before the valve means is operative to open thecommunication controlled thereby.

Another object of the invention is to provide an improved device forcontrolling emergency `applications of the brakes..

Other objects of the invention and features of novelty will be apparentfrom the following description taken in connection with the accompanyingdrawing, the single gure of which is a diagrammatic view, largely insection, of a brake equipment embodying this invention.

Referring to the drawing, the brake equipment therein illustratedcomprises a brake pipe I, a brake cylinder 2, an emergency reservoir 4,and a brake controlling valve device indicated generally by thereference numeral 5.

The brake controlling valve device 5 comprises a pipe bracket section 'Ihaving a mounting face thereon against which is secured the emergencyvalve portion 8 provided by this invention, while the pipe bracketsection 1 has another mounting face thereon, not shown, against which issecured the service portion, not shown, of the brake controlling valvedevice.

The emergency valve portion 8 provided by this invention is animprovement on the corresponding emergency valve portion of the brakecontrolling valve device shown and claimed in the U. S. Patent No.2,031,213, to Clyde C. Farmer, and only such portions of theconstruction and operation of the valve device are illustrated anddescribed in this application as are essential to the understanding ofthis improvement.

The emergency valve portion 8 comprises a body having a bore therein inwhich is mounted a movable abutment in the form of a piston I0 having atone side thereof a chamber I2, which is connected by way of a passage I3in the pipe bracket section I with a branch pipe I4, which communicateswith the brake pipe I. The piston I0 has at the other side thereof avalve chamber I6 in which is mounted a main slide valve I8, and anauxiliary slide valve 20, which are operated by the piston I0 through astem 22 formed integral with the piston. The valve chamber I6 isconnected by way of a passage I5 with a pressure chamber I'I forme-d inthe pipe bracket section T.

The stem 22 has a bore in the end thereof in which is mounted a plunger24, which is yieldingly pressed against the end of the main slide valveI8 by means of a spring 26.

The end of the valve chamber I6 is closed by means of a cover 2B, andthis cover has a bore therein in which is mounted a plunger 30, which isadapted to be engaged by a shoulder 32 on the piston stem 22, and by aprojection 34 on the end of the main slide valve I8. The plunger 30 lsyieldingly urged to the right, as viewed in the drawing, .by means of acoil spring 36, while movement of the plunger in this direction islimited by engagement of the plunger with the body of the emergencyportion.

The main slide valve I8 is held in engagement with its seat by means ofa strut 38, which engages one face of a diaphragm 48. The other face ofthe diaphragm 40 is subject to the pressure of the fluid in a chamber42, which is constantly connected by way of a passage and pipe 44 withthe emergency reservoir 4. The diaphragm 40 is also subject to thepressure of a spring 46 which is mounted in the chamber 42.

The body of the emergency portion 8 has formed therein a chamber 80,which is constantly connected by a passage 62 with the passage I3 in thepipe bracket section "I, and thereby through the branch pipe I4 to thebrake pipe I. An accelerated release check valve 64 is mounted in thechamber 60 and is yieldingly urged by means of a spring 66, intoengagement with a seat rib 68, while a ball check valve 'l0 is mountedin the chamber within the seat rib 68 and is adapted to engage a seatformed on the body I surrounding a passage 'I2 which communicates with aport in the seat of the main slide valve I8.

The body of the emergency portion 8 also has a bore therein in which ismounted a vent valve piston 'I6 having at one side thereof a chamber I8,which is constantly connected by way of a passage with a port in theseat of the main slide valve seat I8.

The chamber on the other face of the piston I8 is open to the atmosphereby way of a passage 82, while the body has a groove 84 therein, which inone position of the piston 'I6 extends around the piston so as to permitcommunication between the chamber 'I8 and the chamber on the oppositeface of the piston 1B.

The piston 16 has a passage 8B extending therethrough so as to permitfluid to ow from the chamber 'I8 to the chamber on the opposite face ofthe piston, and thence to the atmosphere by way of the passage 82. Thepassage 86 has a choke 88 interposed therein to restrict the rate offlow of fluid from the chamber 18.

The body of the emergency valve portion has a groove formed thereinadjacent the end of the bore in which the vent valve piston 76 ismounted. In this groove is secured a sealing gasket 90, having formedthereon an annular seat rib 92, which is adapted to be engaged by a faceof the piston I8 to cut oli` communication from the chamber I8 aroundthe periphery of the piston 19.

The piston 16 has formed integral therewith a stem 94, which has securedthereon a vent valve 96, which is mounted in a chamber 97 formed in thebody or the emergency portion 8, and which is adapted to engage a seatrib 98 formed on the body of the emergency portion 8. The chamber 91 inwhich the Vent valve 96 is mounted is connected by way of a passage 99with the passage 62, and thereby with the passage I3 in the pipe bracketsection I to which is connected the branch pipe I4. leading to the brakepipe I, while the valve 9S is yieldingly urged by means of a spring |00into engagement with the seat rib 98.

The emergency portion shown in the drawing has valve means indicatedgenerally by the reference numeral |05 for controlling the supply of uidunder pressure from the brake pipe to the valve chamber |6 and thepressure chamber I'l.

As shown in the drawing, the valve means |05 comprises a diaphragm I0?,which is urged into engagement with a seat rib |99 by means of a springIII acting through a spring seat IIS, which engages a face of thediaphragm. The spring III is mounted in a chamber I|5 which isconstantly connected with the atmosphere by Way of a passage I I'I.

The chamber IIB within the seat rib |09 is constantly connected by wayof a passage I2! with a port in the bore in the body of the valveportion in which the piston I9 is mounted. The passage I2I has a choke|23 interposed therein.

In the emergency valve portion provided by my invention a valve deviceis provided to control the rate of ow of fluid from the valve means tothe valve chamber I5 and pressure chamber I'I. As shown in the drawingthis valve device is indicated generally by the reference numeral |25,and comprises a movable abutment in the form of a diaphragm |27, whichis subject on one side to the pressure of the iiuid in a charnber |29,and on the other side to the pressure of the fluid in a chamber |3I.

The chamber |29 is constantly connected by Way of a passage |33 with thechamber ||9 within the seat rib 09 of the Valve means |05, while thebody of the emergency portion 8 has projections |35 formed thereon whichextend into the chamber |29 and are engaged by the diaphragm |21 tolimit mo-vement of the diaphragm in one direction.

The chamber |3| of the valve device |25 is constantly connected by wayof a passage |31 with the slide valve chamber I6 and the pressurechamber I1, while a valveI |39 is positioned in the chamber |3| and isyieldingly urged by means of a spring |4| away from a seat rib |43surrounding a chamber |45, which is constantly con nected by way of apassage |41 with the chamber |49 outwardly of the seat rib |09 of thevalve means |05.

A passage |5l, having a choke |53 interposed therein, communicates withthe passage |41 and the passage |31.

The valve |33 is adapted to be moved to the seated position by means ofthe diaphragm |21 acting through a plunger |55 which engages one face ofthe diaphragm |21. The plunger I 55 is slidable in a bore in a portionof the body of the emergency portion 8, and. is provided with anenlarged head |511 which is adapted to engage shoulders |59 on the bodyto limit movement of the diaphragm |21 in one direction.

The plunger |55 has a bore there-in in which is mounted a spring I0! anda spring seat |63, which carries a stem |05 which engages the valve |39.Movement of the spring seat |03 by the spring |0| is limited byengagement of the spring seat |63 with an inwardly extending ilange |01on the plunger |55.

The spring |0| provides yielding force transmitting means, whereby thevalve |04 is held seated with a substantially constant pressureregardless of the extent of movement of the diaphragm I 21. As will beunderstood, the spring IGI is proportioned so as to be able to transmitsubstantially greater force to the valve |39 than is exerted by thespring |4| so that the valve |39 may be moved to the seated positionagainst the spring |4|- by force vtransmitted through the spring ISI.

The emergency valve portion provided by this invention is shown in thedrawing in the normal release position, which is the position which itassumes when th-e brake equipment is fully charged. When the brakeequipment is at atmospheric pressure the diaphragm |01 of the valvemeans |05 is heldin engagement with the seat rib |09 by the spring l,while the other parts of the emergency valve portion may be in theposition in which they are shown in the drawing. l,

In initially charging the equipment, fluid under pressure is supplied tothe brake pipe I, and it flows therefrom through the branch pipe I4 tothe passage I3 and to the chamber I2 on the face of the piston I0.

Fluid under pressure supplied to the passage I3 also flows to theservice portion, not shown, of the brake controlling valve device 5, andcauses the piston of this portion to move to the release position inwhich the brake cylinder 2 is connected to the atmosphere, and in whicha communication is opened through which fluid under pressure may flowfrom the passage I3 to the auxiliary reservoir, not shown, and to theemergency reservoir 4 to charge these reservoirs with fluid underpressure.

Fluid under pressure supplied by the service portion of the brakecontrolling valve device to the emergency reservoir 4 liows by way ofthe passage 44 to the chamber 42 on the face of the diaphragm 40, andincreases the force exerted through the stem 38 to maintain the mainslide valve |8 in engagement with its seat.

Fluid under pressure sup-plied from the brake pipe to the passage I3 owstherethrough to the chamber I2 on the face of the piston I0 of theemergency valve portion 8, and on an increase in the pressure of thefluid in this chamber the piston I0 will be moved to the left, as viewedin the drawing, to the normal release position, if it is not already inthat position, which is the position in which it is shown in thedrawing.

On movement of the piston I0 to the normal release positioncommunication is opened between the chamber I2 and the passage |2|through the choke |23 and uid under pressure will flow to the chamber||9 on the face of the diaphragm |01, which at this time is held inengagement with the seat rib |09 by the spring The spring is of suchValue, and the chamber 9 Within the seat rib |09 is of such area, thatthe diaphragm |01 is held in engagement with the seat rib |09 until thepressure of the fluid in the chamber ||9 within the seat rib |09 hasincreased to a predetermined value, such as twelve pounds.

Fluid under pressure supplied to the chamber ||9 flows therefrom by wayof the passage |33 to the chamber |29 on the face of the diaphragm On apredetermined increase in the pressure of the fluid in the chamber |29the diaphragm |21 is moved upwardly, as viewed in the drawing, therebymoving the plunger |55 upwardly, and this movement of the plunger |55 istransmitted through the spring |6| to the spring seat |63 to press thestem |65 against the valve |39 to move this valve against the spring |4|into engagement with the seat rib |43. On movement of the valve |39 tothe seated position, and on further movement of the plunger |55, thespring IGI is compressed and the plunger |55 is moved relative to thespring seat |63. Movement of the plunger |55 in this direction islimited by the engagement of the head |51 of the plunger with theshoulders' |59 on the body of the emergency valve portion 8.

The increase in the pressure of the fluid in the chamber ||9 on the faceof the diaphragm |01 will be accompanied by a similar increase in thepressure of fluid in the chamber I2 on the face of the piston I0, andthe uid under pressure in this chamber exerts a force on the piston I0tending to move it to the left, as viewed in the drawing, to the normalrelease position, if it is not already in this position, so as to fullyopen the port through which the passage |2| communicates with thechamber I2.

Movement of the piston I0 farther to the left, as viewed in the drawing,from the normal release position towards the inner release position, isresisted by the spring 36 acting through the plunger 30, which isengaged by the shoulder 32 of the piston stem 22 and by the projection34 Von the end of the main slide valve I8'. 'I'he various parts of theemergency valve portion are arranged, however, so that the spring 30 andthe plunger 30 are not effective to oppose movement lll of the piston I0in this direction until the piston I0 has moved to a position tocompletely open the port through which the passage |2| communicates withthe chamber I2 on the face of the piston I0.

When the pressure of the fluid in the chamber II9 on the face of thediaphragm |01 has increased to a predetermined relatively high value,such as above twelve pounds, the force exerted by the fluid underpressure in the chamber ||9 on the diaphragm |91 is suflicient toovercome the opposing force of the spring I||, and the diaphragm |01will be moved away from the seat rib |09 so as to permit fluid underpressure to flow from the chamber |I9 past the seat rib |09 to thechamber |49 outwardly of the seat rib |09.

As soon as the diaphragm |01 is moved away from the seat rib |09, andfluid under pressure is supplied to the chamber |49 outwardly of theseat rib |09, the entire area of the face of the diaphragm |01 issubject to the pressure of the fluid in the chambers |I9 and |49, andthe force exerted by this fluid under pressure on the diaphragm |01 willbe substantially greater than that exerted by the fluid under pressurein the chamber I|9 within the seat rib |09. As soon as the diaphragm |01is moved away from the seat rib |09, therefore, there is a substantialincrease in the force exerted by the fluid under pressure on thisdiaphragm, and the diaphragm is thereafter moved very quickly againstthe spring I I I until the spring seat I3 engages a portion of the bodyof the emergency Valve portion 8 to prevent further movement of thediaphragm |01 against the spring Il I,

On the supply of fluid under pressure to the chamber |49 outwardly ofthe seat rib |09 fluid flows therefrom by way of the passage |41 to thechamber |45 on the spring side of the valve |39. However, at this timethe valve |39 is held in engagement with the seat rib |43 by thediaphragm |21 acting through the spring iGI, and fluid under pressurecannot ilow from the chamber |45 to the chamber I3|.

Fluid under pressure supplied to the passage |41 flows to the passageI5| and through the choke |53 to the passage |31, through which it flowsto the chamber' |3| on the face of the diaphragm |21, and to the valvechamber i6 and the pressure chamber I1 to increase the pressure of thefluid in these chambers.

Fluid under pressure continues to flow from the chamber I2 on the faceof the piston I9 through the choke |23 to the passage I2I leading to thechamber I I9, and thence past the seat rib |09 to the chamber |49, andtherefrom by way of the passage |41 and through the choke |53 to thepassage |31 leading to the valve charnber I6 and the pressure chamberI1, and to the chamber I 3|, to increase the pressure of fluid in thesechambers until the pressure therein has substantially equalized with thepressure of the uid in chamber I2.

On an increase in the pressure oi the fluid in the chamber I3| on theface of the diaphragm |21 there is an increase in the force exerted bythe fluid in this chamber on the diaphragm |21 and opposing the forceexerted by the fluid under pressure in the chamber |29 on the oppositeface of the diaphragm |21. When the pressure of the fluid in the chamberI3I has increased approximately to the pressure of the fluid in thebrake pipe, and consequently in the chamber |29 on the opposite face ofthe diaphragm IIS, the force exerted by the fluid under pressure in thechamber I3I, supplemented by the force exerted by the spring |6I actingthrough the plunger |55, will be sufficient to overcome the opposingforce of the fluid under pressure in the chamber' |29, and the diaphragm|21 will be moved downwardly, as viewed in the drawing, therebypermitting the spring I6I to expand.

The spring IGI will expand until the spring seat |63 engages theinwardly extending flange |61 on the plunger |55, and it will thereafterbe ineffective to exert force on the diaphragm |21 and tending to movethe diaphragm against the opposing force of the fluid under pressure inthe chamber |29.

On a slight further increase in the pressure of the fluid in the chamberI3I, which is at substantially the same pressure as the fluid in thechambers I0 and I1, the force exerted by the fluid under pressure in thechamber |3I, supplemented by the force exerted by the spring |4| actingthrough the valve |39, will be sufficient to move the diaphragm |21against the opposing force of the fluid under pressure in the chamber|29, and the diaphragm |21 will thereupon be moved downwardly intoengagement with the projections |35, while the valve |39 will be movedaway from the seat rib |43 by the spring I4| so as to permit fluid underpressure to flow from the chamber |45 to the chamber I3! at a rapidrate.

Fluid under pressure can now flow from the brake pipe to the valvechamber I6 and the pressure chamber I1 past the valve |39, as well asthrough the choke |53, so that the further charging of the valve chamberand the pressure chamber occurs at a rapid rate.

Upon a subsequent reduction in the pressure of the fluid in the brakepipe at a service rate to effect a service application of the brakes,the service portion, not shown, of the brake controlling valve deviceoperates, as described in detail in the above identified patent, toclose the communication through which uid under pressure is suppliedfrom the brake pipe I to the auxiliary reservoir, not shown, and to theemergency reservoir 4. In addition, the service portion operates tosupply fluid under pressure from the auxiliary reservoir to the brakecylinder 2 until the pressure of the fluidl in the auxiliary reservoiris reduced substantially to the pressure at which the pressure in thebrake pipe is reduced.

On a reduction in the pressure of the uid in the brake pipe I at aservice rate, lluid under pressure flows from the valve chamber I6 andthe pressure chamber I1 to the chamber I2 on the face of the piston I0by way of the passage |31 to the chamber ISI, past the unseated valve|39 to the chamber |45, thence by way of the passage I41 to the chamber|49 outwardly of the seat rib m9, past this seat rib to the chamber IIQwithin the seat rib, and thence by way of the passage I2I and throughthc choke I 23 to the chamber |2.

The choke |23 is proportioned to permit fluid under pressure to flowfrom the chambers I6 and |I at a rate which enables the pressure of thefluid in these chambers to be reduced substantially as rapidly as thepressure of the lluid in chamber I2 on the face of the piston I0 isreduced during a reduction in brake pipe pressure at a service rate.

As the pressure ol" the uid in the chambers I6 and I1 is reduced by theflow of fluid therefrom to the brake pipe substantially as rapidly asthe pressure of the iluid in the chamber I2 is reduced during areduction in the pressure of the fluid in the brake pipe at a servicerate, no differential will be developed in the pressure of the uid inthe chambers on opposite sides of the piston IU, and the piston I9,therefore, will remain in the normal release position.

During service applications of the brakes the pressure of the iiuid inthe brake pipe is maintained at a substantial value, and the fluid underpressure in the chambers ||9 and |49 acting on the face of the diaphragm91 maintains the diaphragm I 01 away from the seat rib |99 against theopposing force of the spring I I `Since the diaphragm |21 of the valvedevice is subject to the opposing pressures of the iiuid in the chambersvI3| and |29, which communicate with the valve chamber 6 and with thebrakepipe I, respectively, the valve .|39 will be held away from theseat rib |43 by the spring I4| during `a service reduction in brake pipepressure because, as just described, the uid pressure in the Vvalvechamber I9 is reduced at substantially the same rate as the brake pipepressure is reduced.

` On a subsequent increase in the pressure of the fluid in the brakepipe to effect the release of the brakes, the service portion of thebrake controlling valve device 5 operates as described in detail in theaboveiolentied patent, to release fluid under pressure from the brakecylinder 2, and to open a lcommunication through which fluid underpressure is supplied from the brake pipe to ther auxiliary reservoir,not shown, and to the emergencyreservoir `4.

w On this increase in the pressure of the fluid in the brake pipe therewill be a similar increase in the'pressure of the iiuid in the chamber I2 on the face of the piston Ill, and fluid under pressure will flowtherefrom through the coke |23 to the passage |ZI, and therethrough tothe chamber ||9 on the face of the diaphragm |91 of the Valve means |95.

Fluid under pressure supplied to the chamber I I9 will flow therefrom byway of the passage |33 to the chamber |29 on the face of the diaphragm|21 to increase the pressure of the fluid in this. chamber.

Fluid under pressure supplied to the chamber I9 also ilows past the seatrib |09, as the diaphragm |91 is held away from this seat ribat thistime, to the chamber |49 outwardly of the seat rib, and thence by way ofthe passage |41 to the chamber |45 and past the unseated valve |39 tothe chamber IBI, from which it flows by way of the passage |31 to thevalve chamber i6 and the pressure chamber I1 to increase the pressure of`the fluid in these chambers.

In addition, fluid under pressure supplied to the passage |41 Will flowtherefrom by Way of the passage I5! and through the choke |53 to thepassage |31 leading to the chambers i9 and l1.

As fluid under pressure can flow past the unseated valve |39 to thechamber IBI, and thence to the chambers I9 and I1, it will flow to thesechambers at a relatively rapid rate, and the rate of increase in thepressure of the fluid in these chambers will be substantially as rapidas the rate of increase in the chamber I2 on the opposite face of thepistonI. As a result, substantially no differential will be created inthe pressure of the fluid in the chambers on opposite sides 'of thepiston I9 during this increase in the pressure of the fluid in thebrak-e pipe, and substantially no force will be exerted on, the pistonI9 tending to move it to the left, as viewed in the drawing.,` Thepiston Ill, therefore, will not b-e moved to the inner release position,but will remain in the normal release position.

On an increase in the pressure of the fluid in the chambers |6 and I1'there will be a similar increase in the pressure of the fluid in thechamber |3I of the valve device |25, so that the pressure of the fluidin the chamber |3I will be increased substantially as rapidly as thepressure of the fluid in the chamber |29 on the opposite face of thediaphragm |21. As a result there will be substantially no force exertedthrough the diaphragm |21 tending to move the valve |39 to the seatedposition against the spring I4I, and this valve will be maintained awayfrom the seat rib |||3 by the spring |4| to permit fluid under pressureto flow to these chambers I6 and I1' at a rapid rate.

On a reduction in the pressure of the iiuid in the brake pipe at anemergency rate to effect an emergency application of the brakes, theservice portion, not shown, of the brake controlling valve device 5operates as described in detail in the above identified patent to closethe communication through which fluid under pressure is supplied fromthe brake pipe to the auxiliary reservoir, not shown, and to theemergency reservoir 4, and to supply fluid under pressure from theauxiliary reservoir to the brake cylinder 2.

'When the brake pipe pressure is reduced at an emergency rate, therewill be a back iiow of fluid from the valve chamber I6 of the emergencyportion 3 to the brake pipe by way of the passage 31 and through thechoke |23 as in a service reduction in brake pipe pressure, but sincethe brake pipe pressure is now being reduced at an emergency rate, thepressure on the brake pipe side of the piston will reduce more rapidlythan the pressure in the valve chamber I6 can reduce by flow through therestricted passage or choke |23, and, as a result, a differentialpressure is created in the valve chamber I6 which causes the piston |9and the auxiliary slide valve 29 to be shifted relative to the mainslide valve I8 against the opposing force of the spring 26 actingthrough the plunger 24.

On this movement of the piston I0 and the stem 22 relative to the mainvslide valve I 8, the auxiliary slide valve 29 is moved relative to themain slide valve |8 so as to uncover a port |10 through the main slidevalve I8, which communicates with the passage 8@ leading to the chamber18 on the face of the vent valve piston 19. When the auxiliary slidevalve 29 is moved to a position to uncover the port |19 through the mainslide valve I9, iiuid under pressure from the chamber I6 ows through theport |19 to the passage 80 and therethrough to the chamber 19 on theface of the vent valve piston 19. The rate of flow of fluid underpressure through the passage to the chamber 18 is substantially morerapid than the rate at which fluid under pressure may escape from thechamber 18 through the groove 84 around the piston 16, and through thechoke 88 in the passage 86. a rapid increase in the pressure of theiiuid in the chamber 18 and the vent valve piston 19 will be moved tothe right, as viewed in the drawing, and this movement of the piston 19will be transmitted through the stem 94 to move the vent valve 99 awayfrom the seat ri-b 98 against the opposing force of the spring |99 andof the fluid under pressure in the chamber 91.

On this movement of the piston 1B, the face of the piston is moved intoengagement with the As a result, there will be f lll seat rib 92 on thegasket 90 so as to prevent the escape of fluid under pressure from thechamber 18 around the periphery of the piston.

On movement of the vent valve 98 away from the seat rib 98 a relativelylarge opening is provided through which fluid under pressure suppliedfrom the brake pipe I by way of the branch pipe I4 and the passages |3,62 and 99 to the chamber 91 will escape to the atmosphere by way of theatmospheric passage 82. There will, therefore, be a rapid reduction inthe pressure of the uid in the brake pipeand also in the chamber I2 onthe face of the piston |Il, as this chamber communicates with thepassage I3, and the piston I0 and the stem 22 will be rapidly moved tothe right, as viewed in the drawing, by the higher pressure of the fluidunder pressure in the chamber I6.

The piston I8 and the stem 22 are moved to the right, as viewed in thedrawing, until the face of the piston engages the face of the gasket|12, which is clamped between the emergency portion 8 and the pipebracket section 1. This is the emergency application position of thepiston I0.

On movement of` the piston I0 and the stem 22 a short distance towardsthe application position, a shoulder |14 on the piston stern 22 engagesthe end of the main slide valve I8, so that on further movement of thepiston I0 and the stem 22 towards the application position, the mainslide valve I8 is moved upon its seat and uncovers the end of thepassage so as to permit fluid under pressure in the chamber |6 tocontinue to flow to the passage 80 and therethrough to the chamber 18 onthe face of the vent valve piston 16.

Upon movement of the piston I0 to the emergency application position,the main slide valve I8 is moved so that a cavity |16 thereinestablishes communication between a port in the seat of the slide valveto which is connected the passage 44 leading from the emergencyreservoir 4, and a passage |18 leading to the brake cylinder 2, so thatfluid under pressure will now flow from the emergency reservoir 4 to thebrake cylinder 2.

Fluid under pressure supplied to the chamber 18 at the face of the ventvalve piston 16 will be vented therefrom at a restricted rate throughthe choke 88 and the passage 86 through the piston 16. The volume of thechambers I6 and |1, and the rate of flow of fluid under pressure throughthe choke 88, are proportioned so as to maintain the pressure of the uidin the chamber 18 at a value suicient to hold the piston 16 inengagement with the rib 92 against the opposing force of the spring |08,and thereby hold the vent valve 9G away from the seat rib 98 until thepressure of the fluid in the brake pipe I has been reduced substantiallyto atmospheric pressure.

When the pressure of the fluid in the chamber 18 has been reduced to arelatively low value by the venting cf fluid under pressure therefromthrough the choke 88 and the passage 86, the force exerted by this fluidon the piston 16 is insuiiicient to maintain this piston against theopposing force of the spring acting through the vent valve 96 and thestem 94, and the spring will thereupon move the vent valve 96 intoengagement with the seat rib 98, while the piston 16 will be moved awayfrom the seat rib 92 to the position in which it is shown inthe drawing,in which position the groove 84 extends around the piston 16. When thepiston 16 is moved to this position any fluid under pressure remaininginthe chambers I6 and |1, and in the chamber 18 at the face of thepiston 16, can escape therefrom at a rapid rate through the groove 84around the piston 16, and thence to the atmosphere by Way of the passage82. The chambers I6 and I1, therefore, will be reduced substantially toatmospheric pressure.

On movement of the piston l0 to the application position, the passage|2| is in communication with the chambers IB and I1 so that the pressureof the iiuid in the chambers I I9 and |49 at the face of the diaphragm|01 reduces as the pressure of the fluid in the pressure chamberreduces, and when the pressure on the diaphragm |81 has been reducedsufficiently, the diaphragm will be moved downwardly by the spring Iinto engagement with the seat rib |09.

In addition, the pressure of the fluid in the chambers |29 and |3| onthe opposite sides of the diaphragm |21 of the valve device |25 willreduce as the pressure in the chambers |8 and I1 reduces, and, as thepressure on the opposite sides of the diaphragm |21 is substantiallyequal, the valve |39 will be held away from the seat rib |83 by thespring |4|, while the diaphragm |21 will be held in engagement with theprojections On a subsequent increase in the pressure ofthe fluid in thebrake pipe to effect a release of the brakes, fluid under pressure flowstherefrom by way of the branch pipe |4 to the passage I3 and to thechamber I2 on the face of the piston |0.

When the pressure of the fluid in the chamber I2 has increased to apredetermined relatively low value, the force exerted by this fluidunder pressure on the piston I0, together with the force exerted by thespring 26 acting through the piston stem 22, is sufficient to cause thepiston l0 to be moved away from the gasket |12, if it has not alreadybeen moved away from the gasket by the spring 26 acting alone. On thismovement of the piston I0, the stem 22 and the auxiliary slide valve 2Dare moved relative to the main slide valve I8, and the auxiliary slideValve 20 is moved to a position to cover the end of the passage |10through the main slide valve I8.

As the piston |I| moves towards the normal release position the main`slide valve |8 is moved to cut off communication between the passages 44and |18 by way of the cavity |16, so that communication between theemergency reservoir 4 and the brake cylinder 2 is cut off.

In addition, on this movement of` the main slide valve I8, the end ofthe slide valve covers the end of the passage 80 to cut offcommunication between the valve chamber I6 and the passage 8D, while theslide valve 8 is moved to a position in which the port |10 therethroughcommunicates with the passage 80.

After a certain amount of movement of the piston I0 it will be moved toa position to open communication between the chamber I2 and the portthrough which uid under pressure is supplied from the chamber I2 throughthe choke |23 to the passage |2| leading to the chamber I I9 on the faceof the diaphragm |01 of the valve means |95. Fluid under pressure thussupplied to the chamber |9 will then iiow therefrom through the passage|33 to the chamber |29 on the face of the diaphragm |21 of the valvedevice |25, and on a predetermined increase in the pressure of the nuidin the chamber |29 the diaphragm |21 will be forced upwardly, and itsmovement will be transmitted through the plunger |55 and the spring |6Ito the spring seat |63, and through the stem |65 to the valve |39 tomove this valve/ 75 into engagement with the seat rib |43 against theopposing force of the spring I4I.

Fluid under pressure supplied from the brake pipe I through the passageI2I acts on the area of the diaphragm I'I within the seat rib |09, andwhen the brake pipe p-ressure has been increased to a predetermineddegree suiiicientv to overcome the pressure of the spring III,` thediaphragm IEJ'I will be moved from its seat so as to open communicationfrom the brake pipe to the valve chamber i6 by Way of the restrictedport or choke I 53.

The choke |53 is of much smaller flow capacity than the choke |23, andis proportioned so as to permit fluid to ow therethrough only at arelatively slow rate, and as a result there will be a relatively slowincrease in the pressure of the fluid in the chambers I6 and II, and inthe chamber |3I of the valve device |25.

During the release of the brakes after-an emergency application of thebrakes, the pressure of the uid in the brake pipe is increased at arelatively rapid rate. This rapid increase in brake pipe pressure,especially at the head end of the train is suicient to cause movement ofthe piston I to its inner release position against the resistance of thespring 36, and the slide valve I8 is moved to a position in which thecavity |76 therein establishes communication between the passage i'IBand the passage l2,

Upon movement of the main slide valve I8 to this position, uid underpressure will flow from the brake cylinder 2 and the auxiliaryreservoir, not shown, by Way of the pipe and passage I'IB, and thecavity I'l6 in the main slide valve I8, to the passage 12, and throughthis passage past the ball check valve il! to the chamber within theseat rib 68. On an increase in the pressure of the fluid in the chamberwithin the seatV rib 68 the accelerated release check valve 64 will bemoved away from the seat rib 68 against the opposing force of the spring66, and of the fluid under pressure in the chamber 68, and fluid underpressure will ovv to the chamber 68 and thence by way of the passage 62to the passage |3, which communicates with the chamber |2 on the face ofthe piston I i), and with the branch pipe I4 leading tothe brake pipe I,so as to increase the pressure of the fluid in the brake pipe and in thechamber I2,

The fluid under pressure thus supplied to the brake pipe causes a localincrease in brake pipe pressure at each car which is transmittedserially throughout the train so as to insure movement of the pistons I8of the emergency portions of the brake controlling valve devices totheir inner release positions.

When the pressure of the fluid in the brake cylinder 2 and the auxiliaryreservoir, not shown, and in the brake pipe has substantially equalizedby the ow of fluid under pressure from the brake cylinder and theauxiliary reservoir to the brake pipe, the accelerated release checkvalve 64 is moved into engagement With the seat rib 68 by the spring 66so as to cut off the further flow of uid under pressure from the brakecylinder to the brake pipe, and to prevent back oW of fluid underpressure from the brake pipe to the cylinder 2. Y

If for any reason the increase in the pressure of the iiuid in the brakepipe is not sunicient to immediately cause movement of the piston I8 tothe inner release position against the spring 36, as may occur at therear of a long train, or in a train which includes a number of carsequipped with older types of brake controlling valve devices, the valvedevice |25 operates to insure movement of the piston IU to the innerrelease position.

The pressure of the uid in the brake pipe and in the chamber I2 on theface of the piston III will increase more rapidly than the pressure ofthe uid in the chamber I6 is increased by the flow of uid thereto fromthe brake pipe through the choke |53. As a result there Will be agradually increasing differential between the pressure of the fluid inthe chambers |2 and I6 on the opposite sides of the piston I0, and acorresponding gradual increase in the force tending to move the pistonIIJ against the resistance of the spring 36. When this differential hasincreased to a predetermined amount the force exerted on the piston II)is great enough to move it against the spring 36, and the piston and theslide valve |8 Will thereupon be moved to the inner release position.

During the time that the piston I0 and the I main slide valve I8 are inthe inner release position, iiuid under pressure continues to flow fromthe chamber I2 through the choke |53 to the chambers I6 and I'I, and t0the chamber |3| of the valve device |25, and after a time interval thepressure of the fluid in the chambers I6 and I'I will have increased toa value such that the force exerted on the piston ID by the fluid underpressure in the chamber I6, together with the force exerted by thespring 36 acting through the plunger 30, is sufficient to overcome theopposing force exerted on the piston I0 by the fluid under pressure inthe chamber I2. The piston |0 and the main slide valve I8 will thereuponbe moved by the spring 36 acting through the plunger 3D, and by thefluid under pressure in the chamber I6 acting on the piston I0, to theright, as viewed in the drawing, from the inner release position to thenormal release position. The plunger 3|) is able to move the main slidevalve I8 at this time as the plunger 30 is engaged by the projection 34on the main slide valve.

When the piston III and the main slide valve I8 have been moved to thenormal release position, the plunger engages a portion` of the body ofthe emergency portion 8 which prevents further movement of the plunger3l) with the result that the spring 36 is no longer effective to exertforce on the piston I0 and the stem 22, or on the main slide valve I8,and the higher pressure of the iluid in the chamber I2 on the face ofthe piston I0 prevents further movement of the piston II) by the uidunder pressure in the Valve chamber I6.

The rate of ow of iiuid under pressure through the choke |53 is suchthat the pressure of the fluid in the chambers I6 and |'I will not haveincreased to a value suilicient to cause the piston IU and the mainslide valve I8 to move from the inner release position to the normalrelease position until after the piston I0 and the main slide valve I8have been in the inner release position for a period of time long enoughto permit the fluid under pressure from the brake cylinder 2 and in theauxiliary reser- Voir, not shown, to flow to the brake pipe I andsubstantially equalize the pressure of the fluid in the brake cylinderand auxiliary reservoir and in the brake pipe.

After movement of the piston Ii] to the normal release position, fluidunder pressure continues to flow from the chamber I2 through the chokel|23 to the passage |2| and thence to the cham bei' I I9, from which itflows past the seat rib |09 to the chamber |49, and therefrom by way ofthe passage |41 to the passage |5I, and through the choke |53 to thepassage |31 leading to the chambers I6 and I1.

In addition, fluid under pressure supplied to the passage |31 flows tothe chamber I3| cn one side of the diaphragm |21 of the valve device|25, while the diaphragm I 21 is subject on the other side to thepressure of the fluid in the chamber |29. The chamber |29 is connectedby way of the passage |33 with the chamber H9, which communicates withthe chamber I2, and thereby with the brake pipe through the passage |2Iand the choke |23, which is of relatively large flow capacity. Thepressure of the fluid in the chamber |29, therefore, will be atsubstantially the pressure of the fluid in the vchamber I2.

When the pressure of the fluid in the chamber |3| has increased to avalue such that the differ ence between the pressure of the fluid in thechamber |3|, and in the chamber |29 on the opposite face of thediaphragm |21, is less than the predetermined amount, the spring 16|will expand and move the diaphragm |21 and the plunger |55 -downwardlyuntil the spring seat |63 engages .the inwardly extending flange |31 onthe plunger |55.

On a further reduction in the differential be#- tween the pressure cfthe fluid in the chamber |3|, and in the chamber |29, the spring I4|will move the valve |39 downwardly away from the seat rib |43, and thismovement of the valve |313A will be transmitted through the stem |65 andthe spring IGI to'move the diaphragm |21 into engagement with theprojections |35.

After movement of the valve |39 away from the seat rib |43, fluid underpressure supplied to the passage |41 ows to .the chamber |45 and thenpast the seat rib |43 to the chamber 31, and therefrom by way of thepassage |31 to the chambers I6 and I1 to increase the pressure of fluidin these chambers at a relatively rapid rate until the pressure of thefiuid in these chambers has equalized with the pressure of the fiuid inthe chamber I2, and in the brake pipe I.

On an increase in the pressureof the fluid in the brake pipev I uidunder pressure flows therefrom by way of the branch pipe I4 and thepassages in the pipe bracket section 1 to the service portion, notshown, ofy the brake controlling valve device 5, and when the pressureof the fluid supplied from the brake pipe I to the service portion hasincreased to a value exceeding the pressure of the fiuid in theauxiliary reservoir, the service portion operates, as described indetail in the above identified patent, to release fluid under pressurefrom the brake cylinder 2, and to open a communication through whichfluid under` pres sure may be supplied from the brake pipe I to theauxiliary reservoir, not shown, and to the emergency reservoir 4.

It will be seen that the rate of flow of fluid from the brake pipe tothe valve chamber I5 of the emergency portion El and the pressure chamber I1 is controlled by the valve device |25, and that this valve deviceincorporates a diaphragm for operating the valve employed therein forrestricting the flow of fluid to the chambers I5 and I1. This diaphragmmay be of substantial area so that adequate force is available to insuremovement of the valve to the closed position.

It will be seen also that during a release of the brakes-after anemergency application of the brakes, fluid under pressure is supplied tothe chamber on the face of this diaphragm before fluid is supplied .tothe passage leading to the chambers I6 and I1, with the result that thevalve device |25 is operated to restrict the flow capacity of thepassages leading to the chambers I9 and I1 before any fluid is suppliedto these chambers. This insures that `the rate of increase in thepressure of the fluid in the chambers I6 and I1 will be restricted sothat sumcient pressure differential will be developed on opposite sidesof the piston III to cause the piston to move to the inner releaseposition, and to remain in this position for a substantial period oftime.

It will be further seen that fluid under pressure is not supplied to thevalve chamber I6 until a predetermined pressure has been developed inthe brake pipe, and that the chamber at the face of the diaphragm of thevalve device |25 is supplied with fiuid under pressure from the brakepipe, so that a substantial differential in pressure is developed onopposite sides of this diaphragm to move the valve operated thereby tothe seated position. This differential is developed even though the rateof increase in brake pipe pressure is relatively slow, as no fluid issupplied to the valve chamber until a predetermined pressure is built upin the brake pipe.

In addition, it will be seen that the valve device |25 incorporates aspring through which force is transmitted from the diaphragm to thevalve employed therein. This spring serves to limit the amount of forcetransmitted to the valve from the diaphragm, and prevents the valvebeing pressed against its seat with too great force, which might resultin injury to the valve.

While one embodiment of the improved brake controlling valve deviceprovided by my invention has been illustrated and described in detail,it should be understood that the invention is not limited .to thesedetails of construction, and that numerous changes and modificationsmayy be made without departing from the scope of the following claims.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

l. In a fiuid pressure brake, in combination, a brake pipe, and anemergency valve device comprising a movable abutment subject to .theopposing pressures of the fluid in the brake pipe and in a pressurechamber and controlling a communication through which fluid underpressure may ow between the pressure chamber and the brake pipe, valvemeans subject to the opposing pressures of the fluid in the pressurechamber and in an operating chamber for controlling the flow of fluidthrough said communication, said valve means being operative on anincrease in the pressure of the fluid in said operating chamber torestrict the flow of fluid through said communication, and means forsupplying fluid under pressure from the brake pipe to said operatingchamber.

2, In a fluid pressure brake, in combination, a brake pipe, and anemergency valve device comprising a movable abutment subject to theopposing pressures of the fluid in the brake pipe and in a pressurechamber and controlling a communication through which fluid underpressure may flow between the pressure chamber and the brake pipe, valvemeans subject to the opposing pressures of the fluid in the pressure.chamber and in an operating chamber for controlling the flow of iiuidthrough said communication, said valve means being operative on anincrease in the pressure of the uid in said operating chamber torestrict the flow of iiuid through said communication, and meanscontrolled b-y said abutment for supplying fluid under pressure from thebrake pipe to said operating chamber.

3. In a iluid pressure brake, in combination, a brake. pipe, and anemergency valve device comprising a movable abutment subject to theopposing pressures of the uid in the brake pipe and in a pressurechamber and controlling a communication through which fluid underpressure may flow between the pressure chamber and the brake pipe, Valvemeans subject to the opposing pressures of the fluid in the pressurechamber and in an operating chamber for controlling the flow of fluidthrough said communication, said valve means being operative on anincrease inthe pressureof the fluid in said operating chamber to cut othe flow of fluid through said communication, means for supplying fluidunder pressure from the brake pipe to said operating chamber, and a.by-pass. passage extending around said valve means through which iluidmay flow from the brake pipe to the pressure. chamber at a restrictedrate.

4l. In a fluid pressure brake, in combination, a brake pipe, and anemergency valve device comprising a movable abutment subject to theopposing pressures of the iluid in the brake pipe and in a pressurechamber and controlling a communication through which fluid underpressure may flow between the pressure chamber and the brake pipe, valvemeans subject to and operated on an increase in the pressure of thefluid supplied to said communication from the brake pipe to opencommunication therethrough, a valve device subject to the opposingpressures of the fluid in the pressure chamber and of the fluid in anoperating chamber for controlling the flow of fluid between the pressurechamber and said valve means, and means ior supplying fluid underpressure from the brake pipe to said operating chamber.

5. In a fluid pressure brake, in combination, a brake pipe, and anemergency valve device comprising a movable abutment subject to theopposing pressures of the fluid in the brake pipe and in a pressurechamber and controlling a communication through which fluid underpressure may ilow between the pressure chamber and the brake pipe, valvemeans subject to and operated on an increase in the pressure of thefluid supplied toi said communication from the brake pipe. to opencommunication therethrough, a valve device subject to the opposingpressures of the fluid in the pressure.` chamber and of the fluid in anoperating chamber for controlling the flow of fluid between the pressurechamber and said valve means, and means controlled by said abutment forsupplying uid under pressure from the brake pipe to said operatingchamber.

6. In a uid pressure brake, in combination, a brake pipe, an emergencyvalve device comprising a movable abutment subject to the opposingpressures of the fluid in the brake pipe and in a pressure chamber andcontrolling a communication through which fluid under pressure may flowbetween the brake pipe and the pressure chamber, valve means subject toand operated on a predetermined increase in the pressure of the uidsupplied from the brake pipe to said communication. to opencommunication therethrough, a valve device subject to the opposingpressures of the fluid in the pressure chamber and in an operatingchamber for controlling the rate of ow of fluid through saidcommunication, and means for supplying fluid under pressure from thebrake pipe to said operating chamber.

7. 'In a fluid pressure brake, in combination, a brake pipe, anemergency valve device comprising a movable abutment subject to theopposing pressures of the fluid in the brake pipe and in a pressurechamber and controlling a communication through which fluid underpressure may flow between the brake pipe and the pressure chamber, valvemeans subject toand operated on a predetermined increase in the pressureof the fluid supplied from the brake pipe to said communication to opencommunication therethrough, a valve device subject to the opposingpressures of the fluid in the pressure chamber and in an operatingchamber for controlling the rate of flow of iiuid through saidcommunication, and means controlled by said abutment for supplying fluidunder pressure from the brake pipe to said operating chamber.

8. In a fluid pressure brake, in combination, a brake pipe, a brakecylinder, valve means movable to a back-dump position to supply fluidfrom the brake cylinder to the brake pipe, yielding means opposingmovement of the valve means to said back-dump position, a movableabutment subject to the opposing pressures of the fluid in the brakepipe and in a pressure chamber for operating said valve means and forcontrolling a communication through which fluid may flow between thebrake pipe and the pressure chamber, a valve device subject to theopposing pressures of the fluid in the pressure chamber and of the fluidin an operating chamber for controlling the iiow of fluid from the brakepipe to the pressure chamber through said communication, and means forsupplying fluid under pressure from the brake pipe to said operatingchamber.

9. In a uid pressure brake, in combination, a brake pipe, a brakecylinder, Valve means movable to a back-dump position to supply fluidfrom the brake cylinder to the brake pipe, yielding means opposingmovement of the valve means to said back-dump position, a movableabutment subject to the opposing pressures of the iiuid in the brakepipe and in a pressure chamber for operating said valve means and iorcontrolling a communication through which fluid may flow between thebrake pipe and the pressure chamber, a valve device subject to theopposing pressures oi the fluid in the pressure chamber and of the fluidin an operating chamber for controlling the iiow of fluid from the brakepipe to the pressure chamber through said communication, and meanscontrolled by said abutment for supplying fluid under pressure from thebrake pipe to said operating chamber.

l0. In a fluid pressure brake, in combination, a brake pipe, a brakecylinder, valve means movable to a back-dump position to supply iluidfrom the brake cylinder to the brake pipe, yielding means opposingmovement of said valve means to the back-dump position, a movableabutment subject to theopposing pressures of the fluid in the brake pipeand in a pressure chamber for operating said Valve means and forcontrolling a communication through which iluid may flow between thebrake pipe and the pressure chamber, Valve means subject to and operatedon a predetermined increase in the pressure of the fluid supplied fromthe brake pipe to said communication to open communication therethrough,a valve device subject to the opposing pressures of the iluidin thepressure chamber and of the fluid in an operating` chamber for con- Viotrolling the rate of flow of iluid through said communication, and meansfor supplying fluid from the brake pipe to said operating chamber.

11. In a iiuid pressure brake, in combination, a brake pipe, a brakecylinder, valve means movable to a back-dump position to supply fluidfrom the brake cylinder to the brake pipe, yielding means opposingmovement of said valve means to the back-dump position, a movableabutment subject to the opposing pressures of the fluid in the brakepipe and in a pressure chamber for operating said valve means and forcontrolling a communication through which fluid may flow between thebrake pipe and the pressure chamber, valve means subject to and operatedon a predetermined increase in the pressure of the fluid supplied fromthe brake pipe to said communication to open communication therethrough,a valve device subject to the opposing pressures of the fluid in thepressure chamber and of the fluid in an operating chamber forcontrolling the rate of floW of fluid through said communication, andmeans controlled by said abutment for supplying uid from the brake pipeto said operating chamber.

i2. In a uid pressure brake, in combination, a brake pipe, and anemergency Valve device comprising a movable abutment subject to theopposing pressures of the fluid in the brake pipe and of the fluid in apressure chamber, valve means responsive to and operated on apredetermined increase in the pressure of the fluid supplied thereto tosupply fluid under pressure to the pressure chamber, a valve devicesubject to the opposing pressures of the iiuid in the pressure chamberand of the fluid in an operating chamber for controlling the rate ofsupply of fluid to the pressure chamber by said valve means, and meanscontrolled by said abutment for supplying fluid under pressure from thebrake pipe to said operating chamber and to said valve means. Y

13. In a uid pressure brake, in combination, a brake pipe, an emergencyvalve device comprising a movable abutment subject to the opposingpressures of the brake pipe and of a pressure chamber, a valve devicesubject to the opposing pressures of the pressure chamber and of fluidsupplied from the brake pipe for controlling a communication throughwhich fluid under pressure is supplied from the brake pipe to thepressure chamber, valve means operated by fluid supplied thereto forcontrolling a communication through which said valve device suppliesfluid under pressure from the brake pipe to the pressure chamber, andmeans controlled by said abutment for supplying iiuid from the brakepipe to said valve means.

14. In a fluid pressure brake, in combination, a brake pipe, anemergency valve device comprising a movable abutment subject to theopposing pressures of the brake pipe and of a pressure chamber, a valvedevice subject to the opposing pressures of the pressure chamber and offluid supplied from the brake pipe for controlling a communicationthrough which uid under presa brake pipe, an emergency valve device com-'prising a movable abutment subject to 'the opposing pressures of thebrake pipe and of a pressure chamber, a valve device subject to theopposing pressures of the pressure chamber and of fluid supplied fromthe brake pipe for controlling a communication from a passage to saidpres-- sure chamber, and valve means operated on a predeterminedincrease in brake pipe pressure for supplying uid under pressure fromthe brake pipe to said passage.

16. In a fluid pressure brake, in combination, a brake pipe, anemergency valve device comprising a movable abutment subject to theopposing pressures of the brake pipe and of a pressure chamber, a valvedevice subject to the opposing pressures of the pressure chamber and offluid supplied from the brake pipe for controlling a communication froma passage to said pressure chamber, and valve means operated on apredetermined increase in brake pipe pressure for supplying fluid underpressure from the brake pipe to said passage, said movable abutmentcontrolling the supply of fluid from the brake pipe to said valve means.

17. In a uid pressure brake, in combination, a brake pipe, an emergencyvalve device comprising a movable abutment subject to the opposingpressures of the fluid in a pressure chamber and of the fluid in thebrake pipe, said abutment controlling a communication through Whichfluid under pressure may be supplied from the brake pipe to said chamberthrough a rst restriction and through a second restriction of less flowarea than the first, and a valve device subject to the opposingpressures of the pressure chamber and of fluid supplied from the brakepipe for controlling a by-pass around the second restriction.

18. In a fluid pressure brake, in combination, a brake pipe, anemergency valve device comprising a movable abutment subject to theopposing pressures of the fluid in a pressure chamber and of the fluidin the brake pipe, said abutment controlling a communication throughWhich uid under pressure may be supplied from Vthe brake pipe to saidchamber through a rst restriction and through a second restriction ofless 110W area than the first, a valve device subject to the opposingpressures of the pressure chamber and of fluid supplied from the brakepipe for controlling a by-pass around the second restriction, and valvemeans operated upon a vpredetermined increase in brake pipe pressure foropening communication to permit the flow of fluid supplied through therst restriction to the second restriction.

19. In a uid pressure brake, in combination, a

. brake pipe, and an emergency Valve device subject to the opposingpressures of the fluid in the brake pipe and of the fluid in a pressurechamber, a passage controlled by said abutment through Which uid mayflow in either direction between the brake pipe and the pressurechamber, said passage being adapted to permit uid to flow from thepressure chamber to the brake pipe rapidly enough to reduce the pressureof the fluid in the pressure chamber substantially as rapidly as thepressure of the uid in the brake pipe is reduced in effecting a serviceapplication of the brakes, and a valve device subject to the opposingpressures of the fluid in the pressure chamber and of uid supplied fromthe brake pipe for controlling the rate of flow of fluid through saidpassage.

20. In a fluid pressure brake, in combination, a

"brake pipe, and an emergency valve device subject to the opposingpressures of lthe uid in the brake pipe and of the fluid in a pressurechamber, a passage controlled by said abutment through which fluid mayow in either direction between the brake pipe and the pressure chamber,said passage being adapted to permit uid to flow from` the pressurechamber to the brake pipe rapidly enough to reduce the pressure of theuid in the pressure chamber substantially as rapidly as the pressure ofthe fluid in the brake pipe is reduced in effecting a serviceapplication of the brakes, a valve device subject to the opposingpressures of the fluid in the pressure chamber and of fluid suppliedfrom the brake pipe for controlling the rate of flow of iuid throughsaid passage, and valve means operative on a predetermined increase inthe pressure of uid supplied from the brake pipe to said passage to opencommunication through said passage.

21. In a fluid pressure brake, in combination, a brake pipe, and anemergency valve device comprising a movable abutment subject to theopposing pressures of the fluid in the brake pipe and of the uid in apressure chamber, a communication controlled by said abutment throughWhich fluid may be supplied from the bra-ke pipe to the pressurechamber, Valve means responsive to and operated on a predeterminedincrease in the pressure of the fluid supplied from the brake pipe tosaid communication to permit ow of fluid through said communication, anda valve device subject to the opposing pressures of the iiuid in achamber open to said communication and of the uid in the pressurechamber for controlling the rate of supply of fluid from saidcommunication to the pressure chamber.

HERBERT R. FUEHRER.

